Bug 10847: Open link to vendor's website in new window

Bug 10847: Open link to vendor's website in new window

To test:
- Create a new vendor or edit an existing one
- Make sure you have entered a valid URL for the website
- Click the link from the vendor summary page and verify it opens
  in a new window/tab (depending on your browser configuration)

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit d67ef01814fb4ba1519d66d9ad749dfa64e62a76)
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>